An updated meta-analysis of hemodynamics markers of prognosis in patients with pulmonary hypertension due to left heart disease

Background

Pulmonary hypertension (PH) is associated with a poor prognosis in patients with left heart disease (LHD). Several hemodynamic variables have been shown to predict outcome, including pulmonary vascular resistance (PVR), pulmonary artery compliance (PAC), and the diastolic pressure gradient (DPG). We sought to provide an updated analysis on the association of these variables with prognosis in PH-LHD.

Methods

We performed a systematic literature review including studies reporting association measurements between DPG and/or PVR and/or PAC and death in PH-LHD patients. These hemodynamic variables were extracted to estimate the pooled hazard ratio (HR) of adverse outcome for each one, and cumulative meta-analysis was performed to investigate temporal trends in the effects reported in the literature as well as the impact of sample size.

Results

17 articles were identified, including 9716 patients with LHD, heterogeneous in terms of age, sex, and etiology of cardiac disease. In this large population, we found that PVR (HR, 1.09; 95% CI: 1.06–1.12), DPG (HR, 1.02; 95% CI: 1.01–1.02) and PAC (HR, 0.73; 95% CI: 0.76–0.81) were associated with an increased risk of adverse outcome, albeit with a less solid performance of DPG (Figure 1). Similar results were found when hemodynamic variables were analyzed according to the thresholds commonly applied in clinical practice, or subdividing cohorts according to the underlying LHD (either heart failure with preserved or reduced left ventricular ejection fraction, or valvular heart disease). Furthermore, cumulative metanalysis indicated that these results are consistently stable since 2018 (Figure 2).

Conclusions

Despite the heterogeneity of PH-LHD group and the intrinsic limitations of each variable, PVR, DPG, and PAC have an established prognostic value in PH-LHD. The strongest correlation with PVR and PAC supports their use in defining disease severity and identifying a subgroup of patients at higher risk of adverse outcome. We believe that these results are consistent through the years and unlikely to change with the addition of further studies.

Funding Acknowledgement

Type of funding sources: Private grant(s) and/or Sponsorship.

A meta-analysis of exercise hemodynamics in heart failure with preserved ejection fraction: the relevance of PAWP/CO slope

Background

Exercise right heart catheterization (RHC) is considered the gold-standard test to diagnose heart failure with preserved ejection fraction (HFpEF). However, exercise RHC is an insufficiently standardized technique, and current hemodynamic thresholds to define HFpEF are not universally accepted. We sought to describe the exercise hemodynamics profile of HFpEF cohorts reported in literature, as compared with control subjects.

Methods

We performed a systematic literature review following the PRISMA statement until December 2020. Studies reporting pulmonary artery wedge pressure (PAWP) at rest and peak exercise were extracted. Summary estimates of all hemodynamic variables were evaluated, stratified according to body position (supine/upright exercise). The PAWP / cardiac output (CO) slope during exercise was extrapolated.

Results

Twenty-seven studies were identified, providing data for 2180 HFpEF patients and 682 controls. At peak exercise, HfpEF cohorts showed a summary estimate of PAWP at peak which was twice as high as compared with control cohorts (30; 95% CI: 29–31 mmHg and 16; 95% CI: 15–17 mmHg, respectively), as well as of delta PAWP (15; 95% CI: 14–16 mmHg and 7; 95% CI: 6–8 mmHg, respectively), and of right atrial pressure (18; 95% CI: 16–19 mmHg and 8; 95% CI: 8–9 mmHg, respectively). These differences persisted after adjustment for age, sex, body mass index, body position. Additionally, summary estimates of PAWP at peak performed during supine exercise was slightly higher than that obtained in upright position only for HFpEF cohorts (supine position: 31; 95% CI: 30–32 mmHg vs upright position; 26; 95% CI: 25–27 mmHg, respectively, p-value<0.01). However, peak PAWP values were highly heterogeneous among the cohorts (I2=93%), with a relative overlap with controls (Figure 1). HFpEF had a significantly larger impairment in the hemodynamic response to exercise, witnessed by a steeper summary PAWP/CO slope than controls (3.75; 95% CI: 3.20–4.28 mmHg/L/min and 0.95; 95% CI: 0.30–1.59 mmHg/L/min, p-value <0.0001), even after adjustment for covariates (p=0.007) (Figure 2). Finally, summary estimates of PAWP/CO slope were higher in HFpEF cohorts performing exercise in the supine position compared with those in upright position (p<0.0001 and p=0.0002 at non-adjusted and adjusted analysis, respectively), but not in control cohorts (p=0.135 and p=0.966 at non-adjusted and adjusted analysis, respectively).

Conclusions

Despite methodological heterogeneity across centers, the hemodynamic profile of HFpEF patients is consistent across studies and characterized by a higher left and right filling pressure at rest compared with controls, enhanced by physical exercise. A PAWP/CO slope cut-off >2 mmHg/L/min seems to retain validity also for studies conducted in the supine position, potentially overcoming the need of different supine and upright PAWP cut-offs.

Funding Acknowledgement

Type of funding sources: Private grant(s) and/or Sponsorship.

Early‐onset and severe Pulmonary Arterial Hypertension due to a novel compound heterozygous association of rare VHL mutations: a case report and review of existing data

Very rare cases of pulmonary arterial hypertension (PAH) have been linked to homozygous or compound heterozygous von Hippel–Lindau (VHL) tumor suppressor gene mutations, while heterozygous VHL mutations lead to VHL tumor syndrome. Although those entities are defined, the genotype–phenotype correlation is incompletely understood, and patient management recommendations are lacking. Here, we describe a case of severe early‐onset PAH due to a so‐far unreported compound heterozygous association of VHL mutations and review the existing data.

P4685Validation of noninvasive pulmonary artery pressure/flow relationship: echocardiography vs right heart catheterization

Background

Invasive pressure-flow (P/Q) relationship of the pulmonary circulation can detect the presence of pulmonary hypertension (PH) during exercise and provide information on patients' symptoms and assess disease severity. Doppler-echocardiography was reported to provide accurate but imprecise noninvasive estimates of both resting and exercise pulmonary haemodynamics. However, data on the direct comparison of invasive vs noninvasive approaches to build pressure-flow relationship are scarce.

Purpose

To compare echocardiographic estimates with invasive measurements of P/Q relationship of the pulmonary circulation during exercise.

Methods

Patients undergoing a clinically indicated right heart catheterization and echocardiography were studied at rest and during exercise. The ratio between mean pulmonary artery pressure and cardiac output at peak exercise (TPR), as well as P/Q slope throughout exercise were calculated. Both TPR and P/Q slope are abnormal when ≥3 mmHg/L/min. Echocardiographic estimates were compared with invasive measurements.

Results

Sixty patients were included (mean age 65±14 years, 73% female). PH was present at rest in 38 cases (63%), of precapillary origin in 23 (61%). Heart failure with preserved ejection fraction was diagnosed in 23 patients, of which 17 had no PH at rest. TPR at peak exercise and P/Q slope were abnormal (≥3 mmHg/L/min) in the majority of patients (56 and 45 subjects, respectively).

Echocardiographic estimates of P/Q slope and TPR correlated significantly although weakly with invasive measurements (R2=0.38 and 0.56, respectively, p<0.001). Bias of echocardiography for P/Q slope and TPR was 1.1±4.2 and 0.4±2.9 mmHg/L/min, respectively (figure). Sensitivity of echocardiography to detect an abnormal TPR or P/Q slope (i.e. ≥3 mmHg/L/min) was 100 and 98%, respectively, faced by low specificity (0 and 33%, respectively).

Figure 1

Conclusions

Doppler-echocardiography can provide rather accurate and sensitive but imprecise estimates of pressure-flow relationships of the pulmonary circulation during exercise. This intrinsic imprecision may limit its use in clinical practice.

P4437Exercise limitation in systemic sclerosis: a case-controlled study

Introduction

Interstitial lung disease and pulmonary hypertension are the leading causes of morbidity and mortality in patients with systemic sclerosis (SSc). Exercise-induced dyspnea is the first manifestation of both complications, which explains why the value of resting tests to predict preclinical heart or lung involvement is limited. Cardiopulmonary exercise testing (CPET) offers a comprehensive approach to identify the cause of exercise limitation. However, the role of CPET in SSc patients without demonstrated cardiac and/or respiratory disease has not been extensively investigated.

Aim

We sought to compare the cardiopulmonary adaptation to exercise of SSc patients without cardiac or pulmonary disease vs healthy volunteers.

Methods

SSc patients (normal resting echocardiography and pulmonary functional test) and healthy volunteers were prospectively enrolled. They underwent maximal symptom-limited CPET, exercise echocardiography (EXEcho), and 6 minutes walk test. Results were compared after adjustment for age and gender.

Results

Thirty-nine patients (54±12 years) and 43 healthy subjects (46±11 years) were included.

Workload was lower in patients than controls (84±42 vs 178±58 W, p<0.001), with similar respiratory exchange ratio (1.27±0.11 vs 1.28±0.10, p=0.570) at peak exercise. Patients had lower oxygen uptake (VO2) at peak exercise (17±6 vs 30±8 ml min kg–1, p<0.001), and higher minute ventilation/carbon dioxide production (VE/VCO2) slope (41±8 vs 33±5, p<0.001) than controls (Figure 1). They had higher VE/VCO2 ratio (40±7 vs 30±3, p<0.001) and lower end-tidal pCO2 (PetCO2) (35±5 vs 41±3 mmHg, p<0.001) at the ventilatory threshold (VT). Respiratory reserve was preserved, and peripheral oxygen saturation was normal at peak exercise in both groups.

Resting echocardiography revealed larger left atrium in SSc-patients (24±8 vs 20±7 ml/m2, p=0.013) and higher estimated left atrial pressure (LAP) (10±2 vs 8±2 mmHg, p=0.001) vs controls. At ExEcho, total pulmonary resistance (TPR) was higher (3.2±0.6 vs 2.6±0.5 WU, p=0.003) and right ventricular function markers were lower at peak exercise in patients vs controls, despite similar values at rest. Plasma NT-proBNP was within normal range in all patients.

Walk distance was shorter in SSc-patients vs controls (505±80 vs 624±50 m, p<0.001), and correlated with peak VO2, VE/VCO2 slope, and VE/VCO2 at VT.

In Ssc patients, peak VO2 also correlated with DLCO (r=0.640, p<0.001), with left atrial volume (r=−0.344, p=0.002), and with estimated LAP (r=−0.490, p<0.001) but not with NT-proBNP or lung volumes.

Conclusion

The combination of low peak VO2, high VE/VCO2 slope, low PetCO2, and high respiratory reserve suggests that patients with SSc, without overt cardiac or respiratory disease, present with cardiovascular limitation to exercise. This may be related to latent cardiac dysfunction or pulmonary vascular disease.

Acknowledgement/Funding

This work was partially funded by research grants from GSK, Actelion, and from the Belgian Foundation for Cardiac Surgery.

[Left ventricular hypertrophy : how to identity the cause ?]

Left ventricular hypertrophy (LVH) is defined by an increase in left ventricular mass. LVH can be adaptive and related to an increase in left ventricular pressure or volume load, or can be related to a primary myocardial disease including sarcomeric, inflammatory or infiltrative disorders. The prevalence of left ventricular hypertrophy increases with age, and its presence is a risk factor for cardiovascular events and death. Recognizing the exact condition underlying LVH is a key step to provide an optimal medical management of those patients, including risk stratification, prognosis and treatment. By the use of multimodal imaging, by the appropriate use of genetics, and by considering clinical, electrical and biological red flags, the identification of the underlying disease becomes more and more achievable in the clinics, without the need for a myocardial biopsy. This review describes the recent diagnostic advances for the medical management of left ventricular hypertrophy.

Characterization of a novel VPAC(1) selective agonist and identification of the receptor domains implicated in the carboxyl-terminal peptide recognition

Vasoactive Intestinal Polypeptide (VIP) interacts with a high affinity to two subclasses of G protein coupled receptors named VPAC(1) and VPAC(2), and has a 3 - 10 fold preference for VPAC(1) over VPAC(2) receptors. Selective ligands for each receptor subclass were recently described. [R(16)]-PACAP (1 - 23) and [L(22)]-VIP are two selective VPAC(1) agonists. Chimaeric human VPAC(2)-VPAC(1) recombinant receptors expressed in CHO cells were used to identify the receptor domains implicated in these two selective ligands recognition. The VPAC(2) preference for [R(16)]-PACAP (1 - 27) over [R(16)]-PACAP (1 - 23) did not require the receptor's NH(2)-terminus domain but involved the whole transmembrane domain. In contrast, the selectivity of [L(22)]-VIP depended only on the presence of the NH(2) terminus and EC(2) domains of the VPAC(1) receptor. The present data support the idea that in the GPCR-B family of receptors the different selective ligands require different domains for their selectivity, and that the peptides carboxyl terminal sequence (amino acids 24 - 27) folds back on the transmembrane receptor domain, close to the peptides, aminoterminus.